On Jan 16, 2009, at 16:12, "Ramiro Blanco" <ramiblanco@xxxxxxxxx> wrote:
2009/1/13 Steven
The classic example is running a mail server
with lots of small files in the same directory, and the solution is to
have a number of separate directories. The issue in that case is that
creating and deleting files requires exclusive access to the directory
in which the files are being created and deleted and thus the
application has to lay out its files such that all the nodes are not
all
trying to do that in just one single directory at once.
So, you mean that when a node wants to write to a file locks the
whole dir? In that case i would have a problem there because moodle
saves lots (eventually thousands) of session files on a single dir
It can make a huge difference to performance, and its not something
which can really be fixed at a filesystem level,
I guess i would have to split that session dir in several dirs if
that's the case.
I think Steven's referring to the creation of many small files in a dir.
The issue at play is that the node must grab a write lock on the
directory inode in order to add a dentry.
The same thing applies to other dentry changes. If you're only
modifying inodes, and not the dentries themselves, you can focus your
tuning efforts elsewhere.
Hth,
-paul
--
Linux-cluster mailing list
Linux-cluster@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/linux-cluster
